I. Field
The following relates generally to wireless communication, and more specifically to allocation of wireless resources to access communications to facilitate improved access for semi-planned or unplanned wireless networks.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, e.g. voice content, data content, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth.
Wireless messages are typically sub-divided in time, frequency, according to codes, and so on, to coordinate communication between access point and access terminal, and to reduce interference between multiple concurrent transmissions. For instance, in an orthogonal frequency division multiple access (OFDMA) system, forward link messages are segmented into time and frequency subdivisions. As one example, a signal can be considered two-dimensional comprising time and frequency, and segmented into multiple frequency sub-bands, and multiple time sub-frames. Each time-frequency sub-division is considered a resource of the OFDMA wireless signal. Furthermore, sets of resources can be configured to carry particular data. For instance, in each time sub-frame, frequency sub-bands at the edge of a spectrum bandwidth can be blanked to reduce cross-talk (guard bands), one set of sub-bands can be reserved for acquisition and control information, another set can be reserved for traffic data, and so on. By analyzing particular frequencies, a device receiving the signal can extract the acquisition and control information from the signal, ignore irrelevant user traffic, and the like.
Further to the above, control and acquisition information is typically set apart (e.g., in time or frequency) from a traffic-related portion of a wireless signal. As an example, pilot signals carrying network acquisition data are often transmitted on multiple frequency channels, distributed throughout a frequency spectrum employed for the wireless signal. In some systems, pilot signals can also be transmitted at higher amplitude than traffic signals, or even other control signals. This arrangement can yield improved distinction of application-related information and acquisition information at a receiver.
Upon identifying a pilot signal, a receiving device typically analyzes the signal to identify a source of the signal. For instance, a transmitting base station typically includes a distinct identifier or code into its pilot signals. The identifier can be used to distinguish the base station from other access points, as well as identify a network associated with the access point. In some cases, a pilot signal might also specify default uplink resources for transmitting an acquisition probe to the base station. In general though, once a pilot signal is obtained, a receiving device can determine whether and how to proceed in communicating with the transmitting base station.
Recent advancements in wireless communications have seen various types of base stations deployed within a common area, resulting in a heterogeneous access point network. Although such networks can be useful to provide different kinds of wireless communication for different subscribers, additional complexities can result. For instance, typical interference reduction techniques that work well for planned, homogeneous base station deployments may not be as effective in unplanned or heterogeneous access point networks. Accordingly, current development efforts in wireless communications involve signal access and acquisition techniques for restricted access base stations, low and medium power base stations, unplanned deployments, and various combinations thereof.